1. Field of the Invention
The present invention relates to an image forming apparatus equipped with a maintenance mechanism which is used for maintaining a line head, and is folded to be stored.
2. Description of the Related Art
Heretofore, in an image forming apparatus, for example, an inkjet printer, for forming an image by ejecting a plurality of colored inks toward a recording medium, a maintenance mechanism is provided in order to protect a recording head and prevent a nozzle from clogging or restore the clogged nozzle to its original state.
The image forming apparatus is roughly classified into a type in which an image is formed by scan-moving a recording head with respect to a recording medium, and a type in which an image is formed by causing a fixed recording head to eject ink toward a recording medium being conveyed. The fixed-head type image forming apparatus usually incorporates a line recording head having a length spanning the entire width of a recording medium. Hence, with an increase in the size of the recording medium, the length of the line recording head becomes longer. In order to perform maintenance of a large-sized line recording head, a similarly large-sized maintenance mechanism is therefore needed.
The maintenance mechanism is normally present at either one of a maintenance processing position, at which maintenance is performed in contact with or in close vicinity to the recording head, and a maintenance retraction position, at which the maintenance mechanism is retracted during the recording time during which the recording head is driven. Accordingly, a space in which the retracted maintenance mechanism is to be stored is needed, and hence if the maintenance mechanism is large-sized, the entire apparatus or the installation area also becomes large.
In order to cope with this problem, in, for example, Jpn. Pat. Appln. KOKAI Publication No. 9-141880, a technique is disclosed in which a cap member constituted of a flexible sheet of an elastic member for sealing the ejection surface of the recording head is fixed to a foldable base plate and, when the maintenance mechanism is retracted, the base plate is folded and the cap is deformed, thereby accommodating the maintenance mechanism therein. As described above, the maintenance mechanism is accommodated in a small space, whereby reduction in the conveyance path length in the paper conveying direction, downsizing of the apparatus, and reduction in the installation area are realized.
The maintenance mechanism is, in the retracted state at the time of image formation, deformed into a U-shape together with the base plate and the cap member. That is, while the image forming apparatus is in the image forming state, the cap member is held in the folded state. Hence, there is the possibility that a gap due to a folding effect or creases may occur at the cap member, therefore attention needs to be paid to lowering of the degree of tightness of the seal of the ejection surface of the recording head, while also preventing seepage of ink.